Slurry process for converting hydrocarbonaceous black oils with hydrogen and hydrogen sulfide

ABSTRACT

A catalytic slurry process for hydrorefining a hydrocarbonaceous charge stock containing hydrocarbon insoluble asphaltenes. The process is effected in slurry fashion with the charge stock being admixed with an aqueous solution of a double salt of the catalytically active metal sulfite and ammonium sulfite. The slurry is reacted at conditions including a temperature above about 225* C. and a pressure greater than about 500 p.s.i.g., and in the presence of hydrogen and hydrogen sulfide. The particularly preferred double salt is vanadyl sulfite-ammonium sulfite, and is employed in an amount of 1.0 percent to about 25.0 percent by weight, computed as elemental vanadium.

United States Patent Inventor William K. T. Gleim Island Lake, 111. Appl. No. 5,915 Filed Jan. 26, 1970 Patented Nov. 9, 1971 v Assignee Universal Oil Products Company Des Plaines, 111.

SLURRY PROCESS FOR CONVERTING HYDROCARBONACEOUS BLACK OILS WITH HYDROGEN AND HYDROGEN SULFIDE 4 Claims, No Drawings 11.8. C1 208/108, 23/129, 208/215, 208/251, 252/414, 252/439 1nt.C1 ..B01jl1/74, C10g13/06,C10g 23/16 Field of Search 208/108, 215; 252/414, 439

References Cited UNITED STATES PATENTS 12/1932 Krauch et al. 208/10 Primary Examiner-Delbert E. Gantz Assistant Examiner-G. E. Schmitkons Attorneys-James R. Hoatson, Jr and Robert W. Erickson ABSTRACT: A catalytic slurry process for hydrorefining a hydrocarbonaceous charge stock containing hydrocarbon insoluble asphaltenes. The process is effected in slurry fashion with the charge stock being admixed with an aqueous solution ofa double salt of the catalytically active metal sulfite and ammonium sulfite. The slurry is reacted at conditions including a temperature above about 225 C. and a pressure greater than about 500 p.s.i.g., and in the presence of hydrogen and hydrogen sulfide. The particularly preferred double salt is vanadyl sulfite-ammonium sulfite, and is employed in an amount of 1.0 percent to about 25.0 percent by weight, computed as elemental vanadium.

SLURRY PROCESS FOR CONVERTING HYDROCARBONACEOUS BLACK OILS WITH HYDROGEN AND HYDROGEN SULFIDE The invention described herein is adaptable to a process for effecting the conversion of asphaltenecontaining petroleum fractions into lower boiling hydrocarbon products. More specifically, the present invention is directed toward a slurrytype catalytic process for continuously converting hydrocarbonaceous material such as atmospheric tower bottoms, vacuum tower bottoms (vacuum residuum), crude oil residuals, topped crude oils, coal oil extracts, crude oils extracted from tar sands, etc., all of which are referred to in the art as black oils." In particular, the process described herein affords a high degree of asphaltene conversion into hydrocarbon-soluble products, while simultaneously effecting a substantial degree of hydrorefining in order to reduce the concentration of sulfurous and nitrogenous compounds.

Hydrocarbonaceous black oils contain high molecular weight sulfurous compounds in exceedingly large quantities.

Black oils also contain excessive quantities of nitrogenouscompounds, high molecular weight organometallic complexes, principally comprising nickel and vanadium, and asphaltenic material. The latter is generally found to be complexed or linked with sulfur and, to a certain extent, with the organometallic contaminants. An abundant supply of such hydrocarbonaceous material exists, most of which has a gravity less than 200 API, and which is further characterized by a boiling range indicating that 10.0 percent by volume, and generally more, has a normal boiling point above a temperature of about 1050 F.

The process of the present invention is particularly directed toward the catalytic conversion of black oils into distillable hydrocarbons. Specific examples of black oils, illustrative of those to which the present invention is especially applicable, include a full boiling range Wyoming sour crude oil, having a gravity of about 23.2 API, and containing about 2.8 percent by weight of sulfur, approximately 2,700 p.p.m. of totalnitrogen, a total of about 100 ppm. of metallic contaminants (computed as elemental nickel and vanadium) and an insoluble asphaltenic fraction in an amount of about 8.4 percent by weight; a crude tower bottoms product, having a gravity of 14.3" API, and containing about 3.0 percent by weight of sulfur, 3,800 ppm. of total nitrogen, about 85 ppm. of total metals and about 10.9 percent by weight of asphaltenic materials; and, a vacuum tower bottoms product having a gravity of 70 API, and containing more than 6,000 ppm. of nitrogen, about 4.0 percent by weight of sulfur, more than 450p.p.m. of metallic contaminants Land about 24.0 percent by weight of pentane-soluble asphaltenic material.

With respect to such charge stocks, the principal difficulty heretofore encountered resides in the lack of sufficient catalyst stability in the presence of the asphaltenic compounds and the excessive concentrations of sulfur. The asphaltenic fraction consists primarily of high molecular weight, -nondistillable coke precursors, and are insoluble in light hydrocarbons such as propane, pentane or heptane. In addition to the asphaltenes, sulfurous and nitrogenous compounds, hydrocarbonaceous black oils contain large quantities of metallic contaminants generally in the range of about 50 p.p.m. to as high as 1,000 ppm. by weight, as the elemental metals. A reduction in the concentration of the organometallic contaminants, such as metal porphyrins, is not easily achieved, and to the extent that the same no longer exert detrimental effects with respect to further processing.

The primary purpose of the present invention is to provide an efficient and economical process for the conversion, or hydrorefining of heavy hydrocarbonaceous material containing insoluble asphaltenes, utilizing a solid, unsupported catalyst in slurry admixture with the charge stock. The term hydrorefining," as employed herein, connotes the catalytic treatment, in an atmosphere of hydrogen, of a hydrocarbon fraction or distillate for the purpose'of eliminating and/or reducing the concentration of the various contaminating influences previously described. The present invention involves the present process is founded, resides in the manner in which 1 the vanadium sulfide is caused to be colloidally dispersed within the charge stock.

OBJECTS AND EMBODIMENTS As hereinbefore set forth, a principal'obje'ct of the present invention resides in providing a process for the conversion of petroleum black oils. A corollary object is to convert hydrocarbon-insoluble asphaltenes into hydrocarbon-soluble, lower boiling normally liquid products.

Another object is to effect removal of sulfurous and nitrogenous compounds through the conversion thereof into hydrocarbons, hydrogen sulfide and ammonium.

A specific object of my invention is to effect the continuous decontamination of asphaltenic black oils by providing a slurry process utilizing a solid, unsupported vanadium sulfide catalyst. In conjunction'withthis object, it is the intent to provide a commercially feasible method for dispersing the catalytic vanadium sulfide within the fresh feed charge stock.

These objects are accomplished by admixing the fresh feed charge stock with an aqueous solution of the double salt vanadyl sulfite-ammonium sulfite, and reacting the resultingmixture with hydrogen and hydrogen sulfide whereby the catalytic vanadium sulfide is produced in situ within the reaction zone.

Therefore, in one embodiment, my invention encompasses a process for hydrorefining a hydrocarbon charge stock which comprises admixing said charge stock with an aqueous solution of the double salt vanadyl sulfite-ammonium sulfite and reacting the mixture, at hydrorefining conditions, with hydrogen and hydrogen sulfide.

Other embodiments of my invention reside in the utilization of particular operating conditions and techniques, concentration of reactants, etc. These as well as other objects and embodiments will become apparent from the following more detailed summary of my invention.

SUMMARY OF INVENTION The unsupported catalyst, utilized in the slurry process of my invention, is a vanadium sulfide of nonstoichiometric sulfur content. The use of the term unsupported is intended to designate a catalyst, or catalytic component, which is not an integral part of a composite with a refractory inorganic oxide carrier material. That is, the catalyst is a'nonstoichiometric vanadium sulfide without the addition thereto of extraneous material. While the precise atomic ratio of sulfur to vanadium, in the catalytic, nonstoichiometric vanadium sulfide, is not known with accuracy, the catalytic vanadium sulfidehas a ratio of sulfur to vanadium not less than 0.821, nor greater than 1.811. This is not intended to mean that the vanadium sul fide catalyst has but a single specific sulfur/vanadium atomic ratio, but rather refers to a mixture of vanadium sulfides having sulfur/vanadium atomic ratios in the aforesaid range. Although four oxidation states are known for vanadium, 2, 3, 4, and, 5, The Periodic Table of the Elements, E. H. Sargent and Company, 1964. Only three stoichiometric vanadium sulfides are sufficiently stable for identification. These are: monovanadium sulfide, VS; sesquivanadium sulfide, V 8 and, pentavanadium sulfide, V 8 Handbook of Chemistry and Physics, Chemical RubberPublishing Company, 42nd Edition, Page 680, 1960-1961. However, many literature references are replete with examples of a multitude of identifiable nonstoichiometric vanadium sulfides which are specific compounds in their own right, as shown by their individual X-ray patterns which are distinct and reproducible. Significantly, I have previously found that the catalytic vanadium sulfide is not identifiable with any of the stoichiometric vanadium sulfides. The present invention is primarily directed toward a method for producing the catalytic, nonstoichiometric vanadium sulfide in situ, which method affords a commercially feasible, economical slurry-type process.

As hereinabove set forth, it has been found that colloidally dispersed, nonstoichiometric vanadium sulfides are capable of effecting the hydrorefining of a wide variety of petroleum black oils in a slurry-type process. Furthermore, it has previously been shown that these catalytic vanadium sulfides must necessarily be produced in situ in order to yield more advantageous results. In accordance with the present invention, the production of the finely divided catalytic vanadium sulfide is accomplished by initially dissolving the double salt of vanadyl sulfite-ammonium sulfite in water and commingling the aqueous solution with the fresh feed charge stock. Heretofore, the dispersion has been accomplished by dissolving organic complexes of tetravalent vanadium in the charge stock. However, the high cost of the complexing agent, for example acetyl acetone, or methyl naphthalene, prohibits their use in a commercially scaled process where the fresh feed charge rate may be as high as 40,000 b./d. I have now found that the eventual catalyst can be produced in the reaction system, by introducing thereto an aqueous solution of the double salt, vanadyl sulfite-ammonium sulfite. Under the conditions of operation, the water soon evaporates and the dispersed double salt is rapidly converted to a mixture of vanadium sulfides by the action of hydrogen sulfide in the hydrogen-rich gaseous phase also being introduced in admixture with the charge stock. The hydrogen sulfide content of the gaseous phase varies from about 1.0 mol percent to about 25.0 mol percent. The use of such a solution of the tetravalent vanadium double salt is advantageous in that the resulting vanadium sulfide is more finely and thoroughly dispersed within the charge stock being processed.

The charge stock-aqueous solution is commingled with hydrogen in an amount of from 5,000 to about 10,000 s.c.f./Bbl., which hydrogen contains hydrogen sulfide in the aforesaid range. Following suitable heat-exchange with various hot effluent streams, the temperature of the mixture is further increased to the level desired at the inlet to the reaction zone. Since the reactions being effected are principally exothermic, the temperature of the effluent from the reaction chamber will be higher than the inlet temperature thereto. The inlet temperature is generally controlled at a minimum level of about 225 C., and at higher levels such that the outlet temperature does not exceed about 500 C. Experience indicates that excellent results are generally attainable when the temperature gradient across the reaction chamber is about 380 C. to about 450 C. The reaction zone is maintained under an imposed pressure greater than about 500 p.s.i.g. and preferably at a level of from 1,500 to about 5,000 p.s.i.g.

Although the present process may be effected in an elongated reaction zone with the mixture being introduced thereto in the upper portion thereof, the effluent being removed from a lower portion, an upflow system offers numerous advantages. The principal advantage resides in the fact that the extremely heavy portion of the charge stock has an appreciably longer residence time within the reaction zone, with the result that a greater degree of conversion is attainable, and incoming hydrogen will effectively strip lower boiling products therefrom. Also, the heavy, unconverted asphaltenic material can be withdrawn from the bottom of the reaction chamber along with particles of vanadium sulfide. The internals of the reaction chamber, or vessel, may be constructed in any suitable manner capable of providing the required intimate contact between the charge stock, the gaseous mixture and the catalyst. In some instances, it may be desirable to facilitate distribution by means of perforated trays or other special mechanical devices.

The liquid product efiluent, containing distillable hydrocarbons, along with hydrogen, hydrogen sulfide, ammonia, and normally gaseous hydrocarbons, principally methane, ethane, and propane, are removed from the upper portion of the reaction chamber. A hot flash system, functioning at essentially the same pressure as the reaction chamber in a first stage, and at a substantially reduced pressure in a subsequent stage, serves to separate the overhead product effluent into a principally vaporous phase, the principal portion of which boils below about 800 F. and a principally liquid phase boiling above about 800 F. The latter may be recycled to combine with the fresh charge stock, thereby serving as a diluent, or it may be conveniently employed to facilitate the introduction of the aqueous solution of the vanadyl sulfite-ammonium sulfite double salt to the reaction zone.

The principally vaporous phase passes into a cold, highpressure separator (about 60 F. to about 140 F.), wherein a hydrogen-rich gaseous phase is recovered and recycled, along makeup hydrogen required to supplant that consumed within the reaction chamber. The normally liquid phase from the cold separator, containing some butanes, is generally subjected to fractionation to prepare a charge stock suitable for further processing. The hot flash system may also function to remove all distillable hydrocarbons boiling below any other desired temperature such as 750 F., 950 F., 1050 F., etc.

With respect to the bottom stream from the hot flash system, it may be totally recycled to combine with the fresh hydrocarbonaceous charge stock. However, it is a preferred operating technique to withdraw a drag stream therefrom which contains at least about 10.0 percent by weight of the catalytic vanadium sulfide. Any suitable means may be utilized to separate the solid catalyst and unreacted asphaltenic material from the liquid-phase hydrocarbons, including filtration, settling tanks, a series of centrifuges, etc. A like quantity of the double salt is then added in order to maintain the desired catalyst content of the slurry.

The material withdrawn from the drag stream is separated, for example, by a series of filtration and methyl naphthalene washing techniques. Methyl naphthalene is employed to remove residual, soluble hydrocarbons from the catalyst-containing sludge. The remainder of the catalyst sludge may then be burned in air to produce vanadium pentoxide which is redissolved in ammonium hydroxide; sulfur dioxide is added to produce the double salt, vanadyl sulfite-ammonium sulfite. The salt is redissolved in water and introduced into the reaction chamber to form the catalytic vanadium sulfide as hereinbefore described.

DESCRIPTION OF A PREFERRED EMBODIMENT The fresh feed charge stock in this illustrative embodiment is a sour Wyoming crude oil having a gravity of 23.2 API. The crude oil contains about 2.8 percent by weight of sulfur, 2,700 ppm. by weight of nitrogen and about 8.4 percent by weight of pentane-insoluble asphaltenic material. Analyses further indicate a total of about ppm. of metallic porphyrins, computed as elemental nickel and vanadium.

Vanadium pentoxide is dissolved in ammonium hydroxide, and sulfur dioxide is added thereto to produce the double salt of vanadyl sulfite-ammonium sulfite. The double salt is dissolved in water and admixed with the fresh feed charge stock in an amount such that the concentration of vanadium therein is about 5.0 percent. The reaction zone is pressured to a level of about 3,000 p.s.i.g., utilizing compressive hydrogen recycled in an amount of about 20,000 s.c.f./Bbl.; the hydrogen recycle stream contains about 15.0 mol percent hydrogen sulfide.

The charge stock-aqueous solution-hydrogen mixture is circulated through a block heater at a temperature of about 250 C. for a period of about one hour. The temperature of the block heater is increased to a level such that the temperature gradient, as measured from the reaction zone inlet to the outlet is controlled at about 380 C. to about 450 C. The fresh feed charge rate is about 150 millileters per hour, and makeup hydrogen is added in amount of about 10.0 s.c.f./hr.

After a line-out period, analyses of the normally liquid product effluent, from about an 8-hour test period, indicate greater than about 98.0 percent asphaltene conversion, less than about 10.0 p.p.m. of organo-metallic complexes and a gravity of about 31.0 API. Furthermore, approximately 50 percent of the sulfurous and nitrogenous compounds are converted into hydrocarbons, hydrogen sulfide and ammonia.

I claim as my invention:

1. A process for hydrorefining a hydrocarbon charge stock which comprises admixing said charge stock with an aqueous solution of the double salt of vanadyl sulfite-ammonium sulfite and reacting the mixture, at hydrorefing conditions, with hydrogen and hydrogen sulfide.

2. The process of claim 1 further characterized in that said mixture contains 1.0 percent to about 25.0 percent by weight of said double salt, calculated as elemental vanadium.

3. The process of claim 1 further characterized in that said hydrorefining conditions include a temperature in the range of 225 C. to about 500 C. and a pressure of from 500 p.s.i.g. to about 5,000 p.s.i.g,

4. The process of claim 1 further characterized in that said hydrogen sulfide is in an amount of 1.0 mol percent to about 25.0 mol percent. 

2. The process of claim 1 further characterized in that said mixture contains 1.0 percent to about 25.0 percent by weight of said double salt, calculated as elemental vanadium.
 3. The process of claim 1 further characterized in that said hydrorefining conditions include a temperature in the range of 225* C. to about 500* C. and a pressure of from 500 p.s.i.g. to about 5,000 p.s.i.g.
 4. The process of claim 1 further characterized in that said hydrogen sulfide is in an amount of 1.0 mol percent to about 25.0 mol percent. 